In Britain, as in many other countries, back pain is a major cause of disability, especially in adults of working age. During the decade to 1993, outpatient attendances for back pain rose fivefold, and the number of days of incapacity from back disorders for which social security benefits were paid more than doubled.1 It is unclear whether this represents an increase in the occurrence of diseases affecting the back or a change in people's behaviour when they have symptoms. To address this question we compared the prevalence of low back pain and associated disability in two postal surveys 10 years apart.
Subjects, methods, and results
Both surveys were approved by the relevant local ethics committees. The first was conducted during 1987-8 and obtained information from 2667 men and women randomly selected from the lists of 136 general practitioners in eight geographically dispersed locations in Britain (59% response rate).2 Of these, 2596 were aged 20-59 years at the time of completing the questionnaire. The investigation focused on occupational and other risk factors for back symptoms and included a question about the occurrence of back pain that had lasted for 24 hours or longer during the previous 12 months in an area between the 12th ribs and the gluteal folds (illustrated with a diagram). Those who reported the symptom were asked whether it had made it impossible to put on hosiery (socks, stockings, or tights).
In the second survey, conducted during 1997-8, questionnaires were completed by 10 363 men and women aged 20-59 years who were chosen at random from the lists of 163 general practitioners across Britain (57% response rate).3 This study was designed to assess occupational exposure to vibration and associated health effects and included the same questions about back pain as the earlier investigation.
Over the 10 year interval between the two surveys, the one year prevalence of back pain (directly standardised to the age and sex distribution of the combined samples) rose from 36.4% to 49.1% (95% confidence interval for difference 10.6% to 15.1%). The trend was consistent across all ages in both men and women, and also within social classes and regions (see table). In contrast, the age and sex standardised prevalence of back pain that made it impossible to put on hosiery fell by 0.7% (–0.1% to 1.5%).
Comment
Over a 10 year interval the one year prevalence of back pain rose by 12.7%, but with no increase in the prevalence of symptoms sufficient to prevent people putting on hosiery. This suggests that the rise in outpatient attendances and sickness absence for back disorders is not explained by a greater incidence of severe back disease. We did, however, find a marked increase in the prevalence of less disabling back pain.
The surveys analysed were based on large samples selected in an identical manner, with wide geographical coverage and similar response rates. It is unlikely that the change can be explained by bias or chance. There may have been an increase in back disorders that do not greatly impair spinal flexion, but a more likely explanation is that cultural changes have led to a greater awareness of more minor back symptoms and willingness to report them, and this cultural shift may also have rendered back pain more acceptable as a reason for absence attributed to sickness.4 If this is correct, the solution to the growing economic burden from back pain may lie more in modifying people's attitudes and behaviour than in interventions aimed at reducing physical stresses on the spine.
Table.
One year prevalence* of symptoms of low back pain in 1987-8 and 1997-8 in patients randomly selected from general practitioners' lists. Values are numbers (percentages) of patients unless indicated otherwise
| Men
|
Women
|
||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| No of participants
|
All low back pain
|
Low back pain making it impossible to put on hosiery
|
No of participants
|
All low back pain
|
Low back pain making it impossible to put on hosiery
|
||||||||||||
| 1987-8 | 1997-8 | 1987-8 | 1997-8 | 1987-8 | 1997-8 | 1987-8 | 1997-8 | 1987-8 | 1997-8 | 1987-8 | 1997-8 | ||||||
| Age (years): | |||||||||||||||||
| 20-29 | 261 | 905 | 91 (34.9) | 421 (46.5) | 8 (3.1) | 11 (1.2) | 332 | 1044 | 86 (25.9) | 402 (38.5) | 8 (2.4) | 17 (1.6) | |||||
| 30-39 | 315 | 1442 | 120 (38.1) | 756 (52.4) | 15 (4.8) | 39 (2.7) | 429 | 1464 | 142 (33.1) | 600 (41.0) | 11 (2.6) | 22 (1.5) | |||||
| 40-49 | 303 | 1439 | 112 (37.0) | 812 (56.4) | 9 (3.0) | 61 (4.2) | 368 | 1302 | 165 (44.8) | 624 (48.0) | 13 (3.5) | 42 (3.2) | |||||
| 50-59 | 256 | 1519 | 103 (40.2) | 860 (56.6) | 12 (4.7) | 49 (3.2) | 332 | 1248 | 115 (34.6) | 639 (51.2) | 12 (3.6) | 55 (4.4) | |||||
| Social class†: | |||||||||||||||||
| I and II | 231 | 1597 | 54 (23.0) | 732 (45.3) | 7 (3.0) | 27 (1.5) | 347 | 1210 | 111 (31.9) | 520 (43.4) | 6 (1.8) | 27 (2.5) | |||||
| IIIN | 131 | 517 | 46 (35.1) | 246 (47.9) | 5 (3.8) | 17 (3.4) | 189 | 1253 | 64 (35.2) | 473 (38.0) | 6 (3.0) | 17 (1.3) | |||||
| IIIM | 414 | 1287 | 186 (45.4) | 783 (60.8) | 11 (2.7) | 45 (3.5) | 478 | 204 | 175 (36.4) | 105 (52.9) | 21 (4.3) | 5 (2.8) | |||||
| IV and V | 282 | 918 | 118 (40.9) | 537 (58.5) | 17 (6.3) | 17 (1.9) | 289 | 778 | 103 (37.4) | 378 (48.3) | 8 (3.0) | 9 (1.2) | |||||
| Region§: | |||||||||||||||||
| South West | 98 | 435 | 35 (34.9) | 246 (55.9) | 2 (2.2) | 13 (2.8) | 137 | 323 | 46 (34.2) | 148 (45.8) | 3 (2.3) | 7 (2.1) | |||||
| South East | 111 | 212 | 37 (33.6) | 126 (59.6) | 4 (3.8) | 7 (3.1) | 147 | 264 | 45 (31.2) | 121 (45.8) | 4 (2.5) | 5 (2.0) | |||||
| Eastern | 155 | 217 | 65 (43.3) | 112 (52.0) | 6 (4.8) | 5 (2.4) | 196 | 215 | 74 (37.9) | 82 (38.3) | 9 (4.4) | 7 (3.2) | |||||
| Trent | 204 | 763 | 85 (41.8) | 404 (53.2) | 11 (5.4) | 21 (2.8) | 252 | 724 | 87 (34.9) | 350 (49.0) | 8 (3.2) | 25 (3.7) | |||||
| Northern and Yorks | 149 | 1481 | 69 (48.2) | 781 (52.3) | 14 (10.3) | 48 (3.2) | 201 | 1438 | 66 (33.2) | 615 (43.1) | 5 (2.3) | 24 (1.7) | |||||
| North West | 126 | 501 | 31 (24.4) | 277(54.9) | 2 (1.6) | 15 (2.9) | 192 | 409 | 70 (36.3) | 176 (42.8) | 7 (4.0) | 12 (2.8) | |||||
| Wales | 139 | 316 | 51 (36.6) | 177 (54.9) | 4 (3.2) | 12 (3.7) | 145 | 255 | 47 (32.1) | 138 (55.3) | 3 (2.1) | 11 (4.0) | |||||
| Scotland | 153 | 431 | 53 (34.4) | 240 (55.2) | 1 (0.6) | 12 (2.6) | 191 | 334 | 73 (37.9) | 159 (48.6) | 5 (2.6) | 6 (1.9) | |||||
Prevalence by social class and region was directly standardised to the age distribution of the combined samples from both surveys.
In 1987-8 the social class of married women was classified according to their husband's occupation. In all other cases social class was based on the subject's own occupation. Social class could not be classified for 235 subjects in 1987-8 and 2599 subjects in 1997-8.
Prevalence by region is presented for those regions that included towns surveyed in 1987-8. Because the sampling within each region was geographically localised, these rates may not be representative of those in the region as a whole.
Acknowledgments
We thank the general practitioners who allowed us to approach their patients, and Ian Bowes and Vanessa Cox for their help with the data preparation.
Editorial by Croft
Footnotes
Funding: The contribution of KW to this research was supported by a fellowship provided by Esso UK plc. The second survey was funded by the Health and Safety Executive.
Competing interests: None declared.
References
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